Ach Gott, vom Himmel sieh darein (Oh God, look down
from heaven), BWV 2,[a] is a church cantata by Johann
Sebastian Bach, composed in Leipzig for the second
Sunday after Trinity and first performed on 18 June
1724. It is the second cantata of his second annual
cycle of chorale cantatas, and is based on Martin
Luther's hymn "Ach Gott, vom Himmel sieh darein",
published in 1524 in the first Lutheran hymnal.

In the first and last movements, which use the original
words of Luther's hymn, the style of the music is
"archaic"the instruments include a choir of trombones
doubling the voices. In the first movement the melody
of the chorale is sung by the alto in long notes,
doubled by two oboes. Each line is prepared by fugal
entrances of the other parts on the same theme. The
second movement is a secco recitative, changing to
arioso for two lines that resemble the words of the
chorale, marked adagio. The alto aria is written in
"modern" style with a solo violin in lively figuration.
The bass recitative is accompanied by the strings. In
contrast, the tenor aria is accompanied by a concerto
of the oboes and strings, which are silent in the
middle section until its transition to the da capo. The
closing chorale is a four-part setting.

The work in six movements is scored for three vocal
soloists (alto, tenor, and bass), a four-part choir,
four trombones, two oboes, two violins, viola, and
basso continuo. The trombones play colla parte with the
choir.